This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Malignancy-specific spectral signatures have the potential to detect and characterize breast lesions.However, the full capabilities and limitations of these spectral signatures remains unknown. We propose to test the spectral signatures by testing their temporal and spatial variability, comparing them with conventional ultrasound imaging as well as histopathological tumor features. The ultimate goal will be to demonstrate that the spectral signatures can improve the detection of breast lesions, particularly in populations where standard methods struggle (such as in dense breast tissue).